Year	Percent
1990	89.706
1991	89.609
1992	89.524
1993	89.453
1994	89.398
1995	89.36
1996	89.214
1997	89.091
1998	88.979
1999	88.865
2000	88.74
2001	88.602
2002	88.468
2003	88.332
2004	88.191
2005	88.046
2006	87.86
2007	87.336
2008	86.795
2009	86.232
2010	85.643
2011	85.062
2012	84.47
2013	83.86
2014	83.23
2015	82.581
2016	81.933
2017	81.939
2018	81.941
2019	81.947
2020	81.962
2021	81.998
2022	82.047
2023	82.103
2024	82.155
2025	82.2
2026	82.247
2027	82.289
2028	82.323
2029	82.348
2030	82.363